COL question

[Dusty Miller]

My Speer reloading manual sez the COL for the 25-06 cartridge is 3.250".  However, when I chamber a dummy round into my T/C Encore it comes out 3.160".  How much of a problem is this going to be in terms of increased pressure?  Any suggestions?

[41 mag]

Depending on your load it could mean a significant increase. I would back off at least .010" from your reading and go from there.

The 3.250" length is a standard, but not etched in stone.

One thing to remember is that the Encore is not a bolt action. It might be great for factory load replications, but it might not handle much more pressure than that. You will most likly find your best accuracy / velocity combo, somewhere between .010 and .030" off th lands.

[Dusty Miller]

Thank you 41 mag, I'll start off backing down .030 and see what happens, I appreciate the inpu. 

[PaulS]

The Speer manual uses that o/all length in their testing. If you are going to use a shorter o/all length then you need to reduce your charge and work up. This is more true for powders that come close to filling the available powder space but it is true for all the charges. It really is true that if you change any specification or component in a given load you should back off 10% and work your load up.
With straight wall cases it is easier to approximate the necessary reduction by taking the specified load and reduce it the same percentage that the volume is reduced with the deeper seated bullet. That gets complicated when using a bottle-neck case but it can still be done. In the long run it is just quicker and safer to drop the load 10% and work your way up to find where your accuracy is best.

[Dusty Miller]

That's good info Paul, thank you.